Foil (papermaking), a type of ving under the wire in the wire section of a paper machine creating a vacuum pulse to eliminate water from the stock (fibre/water slurry).

Ultrasonic foil (papermaking), a type of high frequency vibrating foil under the wire, creating cavitation, imploding vacuum bubbles, in the stock on the wire. The shock waves from the imploding bubbles will distribute the fibres more uniform in the paper web and this will give a stronger paper.